It is known in the art of automotive engineering that shift mechanisms, or shift elements, for instance in countershaft transmissions are radial actuated externally by means of the shift forks or shift levers. For example, transmissions are known from DE 43 25 964 and DE 103 02 502 A1 where the shift mechanisms or shift elements each comprise an axially movable sliding sleeve. The sliding sleeves are hydraulically controlled. For that purpose, appropriate cooling oil supply channels are positioned in the shaft which has the gear wheels to be shifted.
A manual transmission is known from the publication DE 102 06 584 A1 in which the gear wheels to be shifted are provided with inner activation and a matched activating mechanism. Hereby, the inner activation of the shift sleeve takes place via a connecting pin which can be moved axially in slots of the hollow shaft. The connecting pin is activated by a co-rotating hydraulic assembly which is integrated into the hollow shaft. The oil supply unit is hereby positioned outside of the hollow shaft. Therefore, a modular construction, where the complete activating mechanism is positioned inside of the hollow shaft, cannot be realized with the known manual transmission.
Furthermore, a mechanism for the activation of a gearwheel, designed as an idle gear of a countershaft constructed transmission, is known to the applicant through a non-published application DE 10 2006 049 274. The transmission assembly comprises two shift mechanisms, each of which shift two idle gears of a layshaft. The shift mechanisms are activated via two activating mechanisms, from the inner layshaft which is designed as a hollow shaft. The activating mechanisms comprise several actuators which are combined in a module. For the assembly of the module, it is inserted into the hollow shaft and finally attached to the hollow shaft.